DESCRIPTION (Investigator's abstract): The goal of the proposed series of studies is to understand the architecture of color processing in the primate visual cortex and its underlying circuitry and connectivity. The project will utilize optical imaging techniques to reveal the color selective regions in V1 and V2, and subsequently guide electrophysiological and anatomical studies examining the functional properties of color cells and their connectivities. We will focus experiments to help resolve the current controversy as to the location and distribution of color cells in V1 and V2. These studies will target color selective and non-color selective regions as visualized by optical imaging and characterize cells in these regions using quantitatively defined color stimulus paradigms. A second major thrust of the proposed research plan is to investigate the substructure of the cytochrome oxidase- rich V2 stripes. Our previous results have shown that single V2 stripes are actually composed of a series of functionally distinct subcompartments, some of which are involved in color processing. We plan to characterize the properties of these V2 subcompartments and then study the pattern of connections, both functionally and anatomically, between these subcompartments and other structures in V1 and V2. It is well known that the sophistication of the receptive field properties of visual cortical cells (both color and non-color) progresses as one examines each successive stage in visual processing. By studying the relationship between the receptive field properties of color cells at several cortical stages, and the connections that these cells make, we will be able to better understand how these cells contribute to color processing as well as general principles in neural circuitry. Overall, we expect that this series o studies will increase our understanding of the architecture, connectivity, and cooperativity between V1 and V2, in the task of color processing, and in visual function as a whole.